This Phase I program seeks to develop a laboratory scale process to fabricate a high strength, continuous hydroxyapatite fiber. A hydroxyapatite fiber would find many uses in bone replacement applications especially those requiring high strength and toughness in a completely biocompatible material. Fabrics of woven hydroxyapatite fiber could be used as scaffolds for bone ingrowth. Composites reinforced with the hydroxyapatite fiber could replace bone in highly loaded areas and would also be useful in replacement of thin sections where a high degree of toughness would be required. Existing fiber handling and textile technologies would be useful to form the hydroxyapatite fiber into shapes simulating the replaced bone. Mechanical properties of hydroxyapatite implants would be tailored to mimick the anisotropic properties of bone so that input stresses to living host bone would be as natural as possible. It is anticipated that any wear products of hydroxyapatite composites would not cause adverse tissue reactions as is sometimes the case with biomaterials currently in use. The laboratory process to make the fiber is based on the sol-gel technique which has been successful in making several commercially viable products in recent years. Small scale trials will be performed and the composition and tensile strength of the fiber will be measured. With these results a continuous process will be designed and its feasibility tested. These Phase I results will form the basis for full process development in Phase II.